(2R,3R)- 2-(2,4-Difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2,3-butanediol Methanesulfonate is a useful synthetic intermediate in the synthesis of Efinaconazole (E435070); a topical antifungal for onychomycosis. (2R,3R)- 2-(2,4-Difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2,3-butanediol Methanesulfonate is also used as a reagent in the synthesis of Ravuconazole (R128000); an ergosterol biosynthesis inhibitor and antifungal.